Cleryman moved diagonally (6)
I believe the answer is:
bishop
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for bishop that I've seen before include "Chesspiece which moves diagonally" , "see supervisor" , "Chess piece and senior religious person" , "Chess piece and senior member of the clergy" , "one of four beginning on board" .)